* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  height: 100vh;
  background-color: #1d1d1d;
  display: flex;
}

.container {
  margin: auto;
  color: white;
  font-size: 70px;
  font-weight: bold;
  position: relative;
}

.container::before {
  content: 'HTML CSS JAVASCRIPT';
  color: aqua;
  position: absolute;
  left: 0;
  top: 0;
  width: 5px;

  white-space: nowrap;
  overflow: hidden;
  border-right: 2px solid aqua;
  animation: animate 8s linear infinite;
  /* 发光效果 */
  filter: drop-shadow(0 0 50px aqua);
}

@keyframes animate {
  0% {
    width: 0;
  }

  100% {
    width: 100%;
  }
}